Multi-User Multiple Input Multiple Output (MU-MIMO) user equipment (UE) grouping with geographic correlation factors

ABSTRACT

A wireless communication network uses Multi-User Multiple Input Multiple Output (MU-MIMO). Network circuitry stores geographic data that indicates geographic containers. Transceiver circuitry wirelessly receives network signaling from User Equipment (UEs) located in the geographic containers. The network circuitry processes the network signaling to determine UE MU-MIMO correlation factors between the UEs and associate the UE MU-MIMO correlation factors with the geographic containers. The network circuitry processes the UE MU-MIMO correlation factors associated with the geographic containers to determine container MU-MIMO correlation factors between the geographic containers. The network circuitry selects UEs for MU-MIMO based on their container MU-MIMO correlation factors. The transceiver circuitry wirelessly transfers MU-MIMO signals to the UEs that were selected based on their container MU-MIMO correlation factors.

TECHNICAL BACKGROUND

Wireless communication networks provide wireless data services towireless user devices. Exemplary wireless data services includevoice-calling, internet-access, and machine communications. Exemplarywireless user devices comprise phones, computers, drones, and robots.The wireless communication networks have wireless access nodes thatexchange wireless signals with the wireless user devices. The wirelesssignals transport user data and network signaling. The wireless accessnodes exchange the user data and network signaling with other networkelements to help deliver the wireless data services. Exemplary wirelesscommunication networks include Fifth Generation New Radio (5GNR)networks and Long Term Evolution (LTE) networks.

The wireless communication networks use a technology called Multi-UserMultiple Input Multiple Output (MU-MIMO). With MU-MIMO, a wirelessaccess node uses the same time and frequency resources for groups of thewireless user devices. Thus, a group of the wireless user devices sharesthe same resource blocks using MU-MIMO. Sharing time and frequencyresources using MU-MIMO can dramatically improve the spectral efficiencyof the wireless communication networks.

To share time and frequency resources using MU-MMO, the wireless accessnodes and the wireless user devices use beamforming and signalprocessing to separate the individual user signals in the sharedresource blocks. For successful MU-MIMO reception, the wireless userdevices should have a small MU-MIMO correlation factor. The MU-MIMOcorrelation factor predicts the likely beam interference for a group ofwireless user devices sharing resource blocks. A group of wireless userdevices that are close to one another have a high MU-MIMO correlationfactor because their beams are so close. A group of wireless userdevices that are distant from one another have a low MU-MIMO correlationfactor because their beams are separated—especially when there is alarge angle at the wireless access node between the wireless userdevices.

The wireless access points execute Physical Layer (PHY) software toprocess Sounding Reference Signals (SRS) from the wireless user devicesand determine received signal strength, Angle-of-Arrival (AoA), andother radio metrics. The wireless access nodes execute Media AccessControl (MAC) software to process the signal strength, AoA, and otherradio metrics to determine the MU-MIMO correlation factors between thewireless user devices. If the MU-MIMO correlation factor between a groupof wireless user devices is low enough, then the MAC schedules the groupof wireless user devices to receive MU-MIMO transmissions over sharedresource blocks.

Unfortunately, the calculation of the MU-MIMO correlation factors forthe wireless user devices is a heavy burden on the processing resourcesof the wireless access nodes.

Technical Overview

A wireless communication network uses Multi-User Multiple Input MultipleOutput (MU-MIMO). Network circuitry stores geographic data thatindicates geographic containers. Transceiver circuitry wirelesslyreceives network signaling from User Equipment (UEs) located in thegeographic containers. The network circuitry processes the networksignaling to determine UE MU-MIMO correlation factors between the UEsand associate the UE MU-MIMO correlation factors with the geographiccontainers. The network circuitry processes the UE MU-MIMO correlationfactors associated with the geographic containers to determine containerMU-MIMO correlation factors between the geographic containers. Thenetwork circuitry selects UEs for MU-MIMO based on their containerMU-MIMO correlation factors. The transceiver circuitry wirelesslytransfers MU-MIMO signals to the UEs that were selected based on theircontainer MU-MIMO correlation factors.

DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a wireless communication network to serve UserEquipment (UEs) using Multi-User Multiple Input Multiple Output(MU-MIMO).

FIG. 2 illustrates the operation of the wireless communication networkto serve the UEs using MU-MIMO.

FIG. 3 illustrates the operation of the wireless communication networkto serve the UEs using MU-MIMO.

FIG. 4 illustrates the wireless communication network that serves UEsusing MU-MIMO.

FIG. 5 illustrates a Fifth Generation New Radio (5GNR) Long TermEvolution (LTE) communication network to serve 5GNR/LTE UEs usingMU-MIMO.

FIG. 6 illustrates a 5GNR/LTE UE that uses MU-MIMO.

FIG. 7 illustrates a 5GNR gNodeB and an LTE eNodeB and that serve5GNR/LTE UEs using MU-MIMO.

FIG. 8 illustrates the 5GNR/LTE communication network to serve the5GNR/LTE UEs using MU-MIMO.

DETAILED DESCRIPTION

FIG. 1 illustrates a wireless communication network 100 to serve UserEquipment (UEs) 101-109 using Multi-User Multiple Input Multiple Output(MU-MIMO). Wireless communication network 100 comprises UEs 101-109,transceiver circuitry 121, network circuitry 122, and network elements123. UEs 101-109 and transceiver circuitry 121 are coupled overrespective wireless links 111-119. Transceiver circuitry 121 and networkcircuitry 122 are coupled over data links 124. Network circuitry 122 andnetwork elements 123 are coupled over data links 125. UEs 101-109 arelocated in a geographic area or volume that is separated into geographiccontainers 001-040. In some examples, geographic containers 001-040comprise two-dimensional areas that are each smaller than 100 meters by100 meters. For clarity, the number of UEs, circuitries, and geographiccontainers has been restricted on FIG. 1, and wireless communicationnetwork 100 typically includes many more UEs, circuitries, andgeographic containers than the amount shown.

Wireless communication network 100 serves UEs 101-109 with wireless dataservices like media-streaming, social-networking, machinecommunications, or some other user application. UEs 101-109 comprisephones, computers, robots, vehicles, sensors, or some other apparatuswith communication circuitry. Network elements 123 comprise Access andMobility Management Function (AMF), User Plane Functions (UPF), MobilityManagement Entity (MME), Serving Gateway (SGW), or some other computersystems with networking software.

Transceiver circuitry 121 comprises antennas, modulators, amplifiers,filters, digital/analog interfaces, microprocessors, memory, and busconnections. Network circuitry 122 comprises microprocessors, memory,user interfaces, and bus connections. In circuitry 121-122, themicroprocessors comprise Digital Signal Processors (DSPs), CentralProcessing Units (CPUs), Graphical Processing Units (GPUs), FieldProgrammable Gate Arrays (FPGAs), Application-Specific IntegratedCircuits (ASICs), and/or the like. The memories comprise Random AccessMemory (RAM), flash circuitry, disc drives, and/or the like. Thememories store operating systems and network applications. Themicroprocessors execute the operating systems and network applicationsto wirelessly exchange network signaling and user data with UEs 101-109over wireless links 111-119 and to exchange network signaling and userdata with network elements 123 over data links 125. Exemplary networkapplications comprise Physical Layer (PHY), Media Access Control (MAC),Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP), RadioResource Control (RRC), Service Data Adaptation Protocol (SDAP), andCommon Public Radio Interface (CPRI).

Network circuitry 122 stores geographic data that indicates geographiccontainers 001-040. The geographic data could be latitude/longitude orsome other geofence parameters. Transceiver circuitry 121 wirelesslyreceives network signaling from UEs 101-109 that are located ingeographic containers 001-040. Transceiver circuitry 121 transfers thenetwork signaling to network circuitry 122 over data links 124. Networkcircuitry 122 processes the network signaling to determine UE MU-MIMOcorrelation factors between UEs 101-109. For example, network circuitry122 may process Sounding Reference Signals (SRS) from UEs 104-105 todetermine signal strength, Angle-of-Arrival (AoA), and/or other radiometrics. Network circuitry 122 then processes the signal strength, AoA,and/or the other radio metrics to determine the UE MU-MIMO correlationfactor between UEs 104-105. If the UE MU-MIMO correlation factor betweenUEs 104-105 is low enough, then network circuitry 122 may pair UEs104-105 to receive MU-MIMO transmissions from transceiver circuitry 121.

Network circuitry 122 processes the network signaling to associate theUE MU-MIMO correlation factors with geographic containers 001-040.Network circuitry 122 locates UEs 101-109 by radio triangulation, UElocation reports, and/or the like. Network circuitry 122 uses the UElocations to associate the UE MU-MIMO correlation factors to thegeographic containers where the UEs are located. For example, Networkcircuitry 122 associates the UE MU-MIMO correlation factor between UEs104-105 with geographic containers 011 and 024 that contain UEs 104-105.

Network circuitry 122 processes the UE MU-MIMO correlation factorsassociated with geographic containers 001-020 to determine containerMU-MIMO correlation factors between geographic containers 001-020. Forexample, network circuitry 122 may average all of the UE MU-MIMOcorrelation factors between geographic containers 011 and 024 todetermine a single container MU-MIMO correlation factor for geographiccontainers 011 and 024. Container MU-MIMO correlation factors for othergroups of geographic containers 001-040 are developed in the samemanner.

Network circuitry 122 selects groups of UEs 101-109 for MU-MIMO based ontheir container MU-MIMO correlation factors. For example, networkcircuitry 122 may select UEs 108-109 for MU-MIMO based on the containerMU-MIMO correlation factor for containers 034 and 038. Network circuitry122 directs transceiver circuitry 121 to wirelessly transfer MU-MIMOsignals to these selected groups of UEs 101-109. Transceiver circuitry121 wirelessly transfers MU-MIMO signals to the selected groups of UEs101-109. The MU-MIMO signals to a particular group of UEs will use thesame time and frequency resource blocks. For a MU-MIMO group comprisingUE 101 and UE 105, UE 101 and UE 105 would share individual downlinkresource blocks.

The number of UE MU-MIMO correlation factors that are used to determinea single container MU-MIMO correlation factor is referred to as thesample size for that container MU-MIMO correlation factor. In someexamples, network circuitry 122 continuously determines new UE MU-MIMOcorrelation factors, new container MU-MIMO correlation factors, and newsamples sizes for the groups of the geographic containers. Networkcircuitry 122 may then use the container MIMO correlation factors whentheir sample sizes are large enough—above a threshold. Network circuitry122 does not use the container MIMO correlation factors that have lowsample sizes—below the threshold. Network circuitry 122 would use the UEMU-MIMO correlation factors to select UEs for MU-MIMO when the containerMU-MIMO correlation factors do not have adequate sample sizes.

Advantageously, network circuitry 122 calculates the container MU-MIMOcorrelation factors to relive the heavy processing burden caused by therepeated calculation of UE MU-MIMO correlation factors.

FIG. 2 illustrates the operation of wireless communication network 100to serve UEs using MU-MIMO. Network circuitry 122 stores geographic datathat indicates geographic containers (201). Transceiver circuitry 121wirelessly receives network signaling from UEs that are located in thegeographic containers (202). Transceiver circuitry 121 transfers thenetwork signaling to network circuitry 122 (202). Network circuitry 122processes the network signaling to determine UE MU-MIMO correlationfactors between candidate UEs (203). Network circuitry 122 uses the UEMU-MIMO correlation factors to pair candidate UEs for MU-MIMO receptionover shared time and frequency resources. Network circuitry 122processes the network signaling to associate the UE MU-MIMO correlationfactors with the geographic containers (204). Network circuitry 122processes the UE MU-MIMO correlation factors associated with thegeographic containers to determine container MU-MIMO correlation factorsbetween the geographic containers (205). Network circuitry 122 selectsgroups of the UEs for MU-MIMO based on their container MU-MIMOcorrelation factors (206). Network circuitry 122 directs transceivercircuitry 121 to wirelessly transfer MU-MIMO signals to the selectedgroups of UEs (206). Transceiver circuitry 121 wirelessly transfersMU-MIMO signals to the selected groups of UEs over shared time andfrequency resources (207).

FIG. 3 illustrates the operation of wireless communication network 100to serve UEs 101-109 using MU-MIMO. Network circuitry 122 receivesgeographic data that indicates geographic containers from a provisioningsystem in network elements 123. Transceiver circuitry 121 wirelesslyreceives network signaling from UEs that are located in the geographiccontainers. Transceiver circuitry 121 transfers the network signaling tonetwork circuitry 122. Network circuitry 122 processes the networksignaling to determine UE MU-MIMO correlation factors between candidateUEs. Network circuitry 122 processes the network signaling to associatethe UE MU-MIMO correlation factors with the geographic containers.

Network circuitry 122 processes the UE MU-MIMO correlation factorsassociated with the geographic containers to generate container MU-MIMOcorrelation factors for groups of the geographic containers. Networkcircuitry 122 selects groups of UEs for MU-MIMO based on their containerMU-MIMO correlation factors. Network circuitry 122 indicates theselected UEs in the MU-MIMO groups to transceiver circuitry 121. Networkcircuitry 122 receives user data for the selected UEs in the MU-MIMOgroups and transfers the user data to transceiver circuitry 121.Transceiver circuitry 121 wirelessly transfers MU-MIMO signals thattransport the user data to the selected UEs in the MU-MIMO UE groups.

FIG. 4 illustrates wireless communication network 100 that serves UEs101-109 using MU-MIMO. Note that the view of FIG. 4 is an elevation viewwhere the earth's surface runs across the bottom of FIG. 4 (the view ofFIG. 1 is a plan view looking down at the earth's surface from above).On FIG. 4, wireless communication network 100 uses three-dimensionalgeographic containers, although two-dimensional geographic containerscould be used in other examples. For clarity, wireless links 111-119,network circuitry 122, network elements 123, and data links 124-125 areomitted from FIG. 4. Transceiver circuitry 111 is depicted as a tower onFIG. 4.

On FIG. 4, UEs 101-109 are located in a geographic volume that isseparated into geographic containers 401-440. By combining FIGS. 1 and4, the geographic containers 101-040 and 401-440 becomethree-dimensional boxes. For example, UE 104 is located in thegeographic container 011/419. UE 105 is located in the geographiccontainer 024/440. In some examples, the geographic containers eachcomprise a three-dimensional volume that is smaller than 100 meters by100 meters by 100 meters.

Network circuitry 122 stores geographic data that indicates geographiccontainers 001/401-040/440. Network circuitry 122 processes the networksignaling to determine UE MU-MIMO correlation factors between UEs101-109. Network circuitry 122 processes the network signaling toassociate the UE MU-MIMO correlation factors with geographic containers001/401-040/440. For example, Network circuitry 122 associates the UEMU-MIMO correlation factor between UEs 104-105 with three-dimensionalgeographic containers 011/419 and 024/440 that contain UEs 104-105.

Network circuitry 122 processes the UE MU-MIMO correlation factorsassociated with geographic containers 001/401-040/440 to determinecontainer MU-MIMO correlation factors between geographic containers001/401-040/440. For example, network circuitry 122 may average all ofthe UE MU-MIMO correlation factors for geographic containers 011/419 and024/440 to determine a single container MU-MIMO correlation factor forthree-dimensional geographic containers 011/419 and 024/440. ContainerMU-MIMO correlation factors for other groups of three-dimensionalgeographic containers are developed in the same manner. Networkcircuitry 122 selects groups of UEs for MU-MIMO based on theirthree-dimensional container MU-MIMO correlation factors. Transceivercircuitry 121 wirelessly transfers MU-MIMO signals to the selectedgroups of UEs 101-109 in the MU-MIMO groups.

FIG. 5 illustrates Fifth Generation New Radio (5GNR) Long Term Evolution(LTE) communication network 500 to serve 5GNR/LTE UEs using MU-MIMO.5GNR/LTE network 500 is an example of wireless communication network100, although network 100 may differ. 5GNR/LTE network 500 comprises5GNR/LTE UEs 501, 5GNR gNodeB 521, LTE eNodeB 522, Access and MobilityManagement Function (AMF) 523, User Plane Function (UPF) 524, MobilityManagement Entity (MME) 525, and Serving Gateway (S-GW) 526. UEs 501 arecoupled to 5GNR gNodeB 521 over a 5GNR link and to LTE eNodeB 522 overan LTE link. 5GNR gNodeB 521 and LTE eNodeB 522 are coupled by X2 links.5GNR gNodeB 521 and AMF 523 are coupled over N2 links. 5GNR gNodeB 521and UPF 524 are coupled over N3 links. LTE eNodeB 522 and MME 525 arecoupled over S1-MME links. LTE eNodeB 522 and S-GW 422 are coupled overS1-U links.

5GNR gNodeB 521 receives geographic data from AMF 523 that indicatesgeographic containers. LTE eNodeB 522 receives geographic data from MME525 (or gNodeB 521) that indicates the geographic containers. 5GNRgNodeB 521 wirelessly receives 5GNR signaling from 5GNR/LTE UEs 501.5GNR gNodeB 521 processes the 5GNR signaling to determine 5GNR MU-MIMOcorrelation factors among UEs 501. LTE eNodeB 522 wirelessly receivesLTE signaling from 5GNR/LTE UEs 501. LTE eNodeB 522 processes the LTEsignaling to determine LTE MU-MIMO correlation factors among UEs 501.NodeBs 521-522 process the network signaling to associate their UEMU-MIMO correlation factors with the geographic containers.

5GNR gNodeB 521 processes the 5GNR UE MU-MIMO correlation factors togenerate 5GNR container MU-MIMO correlation factors for groups of thegeographic containers. LTE eNodeB 522 processes the LTE UE MU-MIMOcorrelation factors to generate LTE container MU-MIMO correlationfactors for groups of the geographic containers. 5GNR gNodeB 521 selectsgroups of UEs 501 for 5GNR MU-MIMO based on their 5GNR container MU-MIMOcorrelation factors. LTE eNodeB 522 selects groups of UEs 501 for LTEMU-MIMO based on their LTE container MU-MIMO correlation factors. 5GNRgNodeB 521 transfers user data to 5GNR/LTE UEs 501 over 5GNR MU-MIMOsignals. LTE eNodeB 522 transfers user data to 5GNR/LTE UEs 501 over LTEMU-MIMO signals.

FIG. 6 illustrates an exemplary one of 5GNR/LTE UEs 501 that usesMU-MIMO. 5GNR/LTE UE 501 is an example of UEs 101-109 although UEs101-109 may differ. 5GNR/LTE UE 501 comprises transceiver circuitry 611,processing circuitry 612, and user circuitry 613 which areinterconnected over bus circuitry. User circuitry 613 comprises graphicdisplays, machine controllers, sensors, cameras, transceivers, and/orsome other user interface components. Transceiver circuitry 611comprises radios for 5GNR and LTE. The radios each comprise antennas,amplifiers (AMPS), filters, modulation, analog/digital interfaces (A/D),Digital Signal Processors (DSP), and memory. The radios may share someof these components by using time diversity, frequency separation, andthe like.

Processing circuitry 612 comprises microprocessors and UE memory. Themicroprocessors comprise CPUs, GPUs, ASICs, and/or some other computercircuitry. The UE memory comprises volatile and non-volatile datastorage like RAM, flash, and/or disk. The UE memory stores an operatingsystem (OS), user applications, and network applications for 5GNR andLTE. The network applications comprise Physical Layer (PHY), MediaAccess Control (MAC), Radio Link Control (RLC), Packet Data ConvergenceProtocol (PDCP), Radio Resource Control (RRC), and Service DataAdaptation Protocol (SDAP). The microprocessors execute the operatingsystem, user applications, and network applications to exchange userdata and network signaling with NodeBs 521-522.

The user applications store Uplink (UL) user data and signaling in theUE memory. The network applications process the UL user data/signalingand Downlink (DL) network signaling to generate UL network signaling.The network applications transfer the UL user data and network signalingto the memories in transceiver circuitry 611. In transceiver circuitry611, the DSP processes the UL user data and network signaling totransfer corresponding digital UL signals to the A/D interfaces. The A/Dinterfaces convert the digital UL signals into analog UL signals formodulation. Modulation up-converts the analog UL signals to theircarrier frequencies. The amplifiers boost the modulated UL signals forthe filters which attenuate unwanted out-of-band energy. The filterstransfer the UL signals through duplexers to the antennas. Theelectrical UL signals drive the antennas to emit corresponding wirelesssignals that transport the UL user data and network signaling to NodeBs521-522.

In the transceiver circuitry 611, the antennas receive wireless signalsthat transport user data and network signaling from NodeBs 521-522. Theantennas transfer corresponding electrical DL signals through duplexersto the amplifiers. The amplifiers boost the received DL signals forfilters which attenuate unwanted energy. In modulation, demodulatorsdown-convert the DL signals from their carrier frequencies. The A/Dinterfaces convert the analog DL signals into digital DL signals for theDSPs. The DSPs recover DL data from the digital DL signals. The DSPstransfer the DL data to the UE memory. The microprocessors execute thenetwork applications to process the DL data to recover the DL user dataand network signaling. The microprocessors execute the networkapplications to store the DL user data and signaling in the UE memory.The user applications process their user data and signaling in the UEmemory.

FIG. 7 illustrates 5GNR gNodeB 521 and LTE eNodeB 522 and that serve5GNR/LTE UEs 501 using MU-MIMO. Node-Bs 521-522 comprise examples ofcircuitry 121-122, although circuitry 121-122 may differ. 5GNR gNodeB521 comprises 5GNR Distributed Unit (DU) circuitry 721 and portions ofCentralized Unit (CU) circuitry 723. LTE eNodeB 522 comprises LTE DUcircuitry 722 and portions of CU circuitry 723. DU circuitry 721-722each comprise antennas, amplifiers/filters, modulation, A/D, DSP/CPU,memory, and DU transceivers (XCVR) that are coupled over bus circuitry.CU circuitry 723 comprises CU microprocessors, CU memory, CUtransceivers, and network (NET) transceivers that are coupled over buscircuitry.

The antennas in 5GNR circuitry 721 are coupled to 5GNR/LTE UEs 501 overwireless 5GNR links. The DU transceivers in 5GNR DU circuitry 721 arecoupled to the CU transceivers in CU circuitry 723 over RLC/PDCP links.The network transceivers in CU circuitry 723 are coupled to AMF 523 overN2 links. The network transceivers in CU circuitry 723 are coupled toUPF 524 over N3 links. In 5GNR DU circuitry 721, the 5GNR memory storesan operating system and network applications for 5GNR PHY, MAC, and RLC.

The antennas in LTE DU circuitry 722 are coupled to 5GNR/LTE UEs 501over wireless LTE links. The DU transceivers in LTE DU circuitry 722 arecoupled to the CU transceivers in CU circuitry 723 over LTE CommonPublic Radio Interface (CPRI) links. The network transceivers in CUcircuitry 723 are coupled to MME 525 over S1-MME links. The networktransceivers in CU circuitry 723 are coupled to S-GW 526 over S1-Ulinks. In LTE DU circuitry 722, the LTE memory stores an operatingsystem and network applications for CPRI. In CU circuitry 723, the CUmemory stores an operating system, virtual layer (VL) components, andnetwork applications. The virtual layer components comprise hypervisormodules, virtual switches, virtual machines, and/or the like. Thenetwork applications include LTE PHY, LTE MAC, LTE RLC, LTE PDCP, LTERRC, and 5GNR PDCP.

In this example, 5GNR DU circuitry 721 hosts the network applicationsfor 5GNR PHY, 5GNR MAC, and 5GNR RLC. CU circuitry 723 hosts the networkapplications for 5GNR PDCP, 5GNR RRC, 5GNR SDAP, LTE PHY, LTE MAC, LTERLC, LTE PDCP, and LTE RRC. In other examples, circuitry 721-723 may useother network application splits.

In 5GNR DU circuitry 721, the antennas receive wireless 5GNR signalsfrom 5GNR/LTE UEs 501 that transport 5GNR SDAP data and RRC signaling.In LTE DU circuitry 722, the antennas receive wireless LTE signals from5GNR/LTE UEs 501 that transport LTE RRC data and RRC signaling. In DUcircuitry 721-722, the antennas transfer corresponding electrical ULsignals through duplexers to the amplifiers. The amplifiers boost thereceived UL signals for filters which attenuate unwanted energy. Inmodulation, demodulators down-convert the UL signals from their carrierfrequencies. The analog/digital interfaces convert the analog UL signalsinto digital UL signals for the DSPs. In 5GNR DU circuitry 721, the 5GNRDSPs recover UL 5GNR symbols from the digital UL 5GNR signals.

The 5GNR CPUs execute the 5GNR PHY, MAC, and RLC to process the UL 5GNRsymbols to recover UL Protocol Data Units (PDUs) that carry SDAP dataand RRC signaling. In particular, the 5GNR PHY processes UL SoundingReference Signals (SRS) to determine UE MU-MIMO correlation factors andUE locations. The 5GNR MAC processes the UE MU-MIMO correlation factorsand UE locations to associate the UE MU-MIMO correlation factors withgeographic containers. The 5GNR MAC processes the UE MU-MIMO correlationfactors for individual groups of geographic containers to determinecontainer MU-MIMO correlation factors for the individual groups ofgeographic containers. The 5GNR MAC selects UEs for MU-MIMO based on thecontainer MU-MIMO correlation factors. The DU transceivers in DUcircuitry 721 transfer the UL 5GNR PDUs to the CU transceivers in CUcircuitry 723 over the 5GNR RLC/PDCP links.

In CU circuitry 723, the CU microprocessors execute the 5GNR PDCP, RRC,and SDAP to recover the UL SDAP data and RRC signaling from the UL 5GNRPDUs. The CU microprocessors execute the 5GNR RRC to process UL RRCsignaling and DL N2 signaling to generate UL N2 signaling. The CUmicroprocessors execute the 5GNR SDAP to process UL SDAP data togenerate UL N3 data. The network transceivers transfer the UL N2signaling to AMF 523 over the N2 links. The network transceiverstransfer the UL N3 data to UPF 524 over the N3 links.

In LTE DU circuitry 722, the LTE DSPs recover UL LTE symbols from the ULdigital LTE signals. The LTE DSPs execute the LTE CPRI to format the ULLTE symbols for transmission. The DU transceivers transfer the UL LTEsymbols to the CU transceivers in CU circuitry 723 over the CPRI links.In CU circuitry 723, the CU microprocessors execute the LTE PHY, MAC,RLC, PDCP, and RRC to recover the UL RRC data and RRC signaling from theUL LTE symbols. In particular, the LTE PHY processes UL SRS to determineUE MU-MIMO correlation factors and UE locations. The LTE MAC processesthe UE MU-MIMO correlation factors and UE locations to associate the UEMU-MIMO correlation factors with geographic containers. The LTE MACprocesses the UE MU-MIMO correlation factors for individual groups ofgeographic containers to determine container MU-MIMO correlation factorsfor the individual groups of geographic containers. The LTE MAC selectsUEs for MU-MIMO based on the container MU-MIMO correlation factors. TheCU microprocessors execute the LTE RRC to process UL RRC signaling andDL S1-MME signaling to generate UL S1-MME signaling and DL RRCsignaling. The network transceivers transfer the UL S1-MME signaling toMME 525 over the S1-MME links. The network transceivers transfer the ULS1-U data to LTE-SGW 526 over the S1-U links.

In CU circuitry 723, the network transceivers receive DL N2 signalingfrom AMF 523 over the N2 links. The network transceivers receive DL N3data from UPF 524 over the N3 links. The CU microprocessors execute the5GNR RRC to process the UL RRC signaling and DL N2 signaling to generateDL RRC signaling. The CU microprocessors execute the 5GNR SDAP toprocess the DL N3 data to generate DL SDAP data. The CU microprocessorsexecute the 5GNR PDCP to process the DL RRC signaling and SDAP data togenerate DL 5GNR PDUs. The CU transceivers transfer the DL 5GNR PDUs to5GNR DU circuitry 721 over the RLC/PDCP links.

In CU circuitry 723, the network transceivers receive DL S1-MMEsignaling from MME 525 over the S1-MME links. The network transceiversreceive DL S1-U data from S-GW 422 over the S1-U links. The CUmicroprocessors execute the LTE RRC to process the UL RRC signaling andDL S1-MME signaling to generate DL RRC signaling. The CU microprocessorsexecute the LTE PDCP, RLC, MAC, and PHY to process the DL RRC signalingand RRC data to generate DL LTE symbols. In particular the LTE MACschedules the UE groups that were selected for MU-MIMO in the sameresource blocks. The LTE PHY transfers the LTE MU-MIMO symbols fordelivery to the UE groups that were selected for MU-MIMO in the sameresource blocks. The CU transceivers transfer the DL LTE symbols to LTEDU circuitry 722 over the CPRI links.

In 5GNR DU circuitry 721, the 5GNR CPU executes the 5GNR RLC, MAC, andPHY to process the DL PDUs to generate DL 5GNR symbols. In particularthe 5GNR MAC schedules UE groups that were selected for MU-MIMO in thesame resource blocks. The 5GNR PHY transfers the 5GNR MU-MIMO symbolsfor delivery to the UE groups that were selected for MU-MIMO in the sameresource blocks.

The 5GNR DSP processes the DL 5GNR symbols to generate correspondingdigital DL signals for the 5GNR A/D. In LTE DU circuitry 722, the LTECPU executes the LTE DSP to process the DL LTE symbols and generatecorresponding digital DL signals for the LTE A/D. In DU circuitry721-722, the A/Ds convert the digital DL signals into analog DL signalsfor modulation. Modulation up-converts the DL signals to their carrierfrequencies. The amplifiers boost the modulated DL signals for thefilters which attenuate unwanted out-of-band energy. The filterstransfer the DL signals through duplexers to the antennas. Theelectrical DL signals drive the antennas to emit corresponding wirelessLTE and 5GNR signals that transport the DL SDAP/RRC data and RRCsignaling to 5GNR/LTE UEs 501.

In CU circuitry 723, the 5GNR SDAP maps between the N3 data and ServiceData Units (SDUs). The 5GNR RRC maps between N2 signaling and SDUs. The5GNR SDAP and RRC exchange their SDUs with the 5GNR PDCP. The 5GNR PDCPmaps between the SDUs and Protocol Data Units (PDUs). The 5GNR PDCPexchange the 5GNR PDUs with the 5GNR RLC in 5GNR DU circuitry 721. In5GNR DU circuitry 721, the 5GNR RLC maps between the PDUs from CUcircuitry 723 and MAC logical channels. The 5GNR RLC exchanges the SDAPdata and RRC signaling with the 5GNR MAC over the MAC logical channels.The 5GNR MAC maps between the MAC logical channels and MAC transportchannels. The 5GNR MAC exchanges the SDAP data and RRC signaling withthe 5GNR PHY over the MAC transport channels. The 5GNR PHY maps betweenthe MAC transport channels and PHY transport channels. The 5GNR PHYexchanges the SDAP data and RRC signaling with PHYs in 5GNR/LTE UEs 501over the PHY transport channels and 5GNR DU circuitry 721.

In CU circuitry 723, the LTE RRC maps between S1-U data and SDUs. TheLTE RRC maps between S1-MME signaling and SDUs. The LTE RRC exchangesthe SDUs with the LTE PDCP. The LTE PDCP maps between the SDUs andProtocol Data Units (PDUs). The LTE PDCP exchange the PDUs with the LTERLC. The LTE RLC maps between the PDUs and MAC logical channels. The LTERLC exchanges the RRC data and RRC signaling with the LTE MAC over theMAC logical channels. The LTE MAC maps between the MAC logical channelsand MAC transport channels. The LTE MAC exchanges the RRC data and RRCsignaling with the LTE PHY over the MAC transport channels. The LTE PHYmaps between the MAC transport channels and PHY transport channels. TheLTE PHY exchange the RRC data and RRC signaling with PHYs in 5GNR/LTEUEs 501 over the PHY transport channels and LTE DU circuitry 722.

RRC functions comprise authentication, security, handover control,status reporting, Quality-of-Service (QoS), network broadcasts andpages, and network selection. SDAP functions comprise QoS marking andflow control. PDCP functions comprise security ciphering, headercompression and decompression, sequence numbering and re-sequencing,de-duplication. RLC functions comprise Automatic Repeat Request (ARQ),sequence numbering and resequencing, segmentation and resegmentation.MAC functions comprise buffer status, power control, channel quality,Hybrid Automatic Repeat Request (HARQ), user identification, randomaccess, user scheduling, and QoS. PHY functions comprise packetformation/deformation, windowing/de-windowing,guard-insertion/guard-deletion, parsing/de-parsing, controlinsertion/removal, interleaving/de-interleaving, Forward ErrorCorrection (FEC) encoding/decoding, rate matching/de-matching,scrambling/descrambling, modulation mapping/de-mapping, channelestimation/equalization, Fast Fourier Transforms (FFTs)/Inverse FFTs(IFFTs), channel coding/decoding, layer mapping/de-mapping, precoding,Discrete Fourier Transforms (DFTs)/Inverse DFTs (IDFTs), and ResourceElement (RE) mapping/de-mapping.

FIG. 8 illustrates 5GNR/LTE communication network 500 to serve 5GNR/LTEUEs 501 using MU-MIMO. In 5GNR gNodeB 521 and LTE eNodeB 522, the MACsreceive geographic data that specifies geographic containers. The MACswill associate MU-MIMO correlation factors with the geographiccontainers.

In 5GNR/LTE UEs 501, the user applications exchange user data and usersignaling with the 5GNR SDAP and RRC. The user applications alsoexchange user data and user signaling with the LTE RRC. The 5GNR RRCprocesses the user signaling and DL RRC signaling to generate UL RRCsignaling. The 5GNR RRC transfers the UL RRC signaling to the 5GNR RRCin 5GNR gNodeB 521 over the 5GNR PDCP, RLC, MAC, and PHY layers. The5GNR SDAP processes the user data to generate SDAP data. The 5GNR SDAPtransfers the SDAP data to the 5GNR SDAP in 5GNR gNodeB 521 over the5GNR PDCP, RLC, MAC, and PHY layers. The LTE RRC processes the usersignaling and DL RRC signaling to generate UL RRC signaling. The LTE RRCprocess the user data to generate UL RRC data. The LTE RRC transfers theUL RRC signaling and the UL RRC data to the LTE RRC in LTE eNodeB 522over the LTE PDCP, RLC, MAC, and PHY layers.

In 5GNR gNodeB 521, the 5GNR RRC exchanges N2 signaling with AMF 523.The 5GNR SDAP exchanges N3 data with UPF 524. The 5GNR RRC processes theDL N2 signaling and UL RRC signaling to generate DL RRC signaling and ULN2 signaling. The 5GNR RRC transfers the RRC signaling to the 5GNR RRCin 5GNR/LTE UEs 501 over the 5GNR PDCP, RLC, MAC, and PHY layers. The5GNR SDAP processes the DL N3 data to generate DL SDAP data. The 5GNRSDAP transfers the SDAP data to the 5GNR SDAP in 5GNR/LTE UEs 501 overthe 5GNR PDCP, RLC, MAC, and PHY layers. In LTE eNodeB 522, the LTE RRCexchanges S1-MME signaling with MME 525 and S1-U data with S-GW 526. TheLTE RRC transfers the RRC signaling and RRC data to the LTE RRC in5GNR/LTE UEs 501 over the LTE PDCP, RLC, MAC, and PHY layers.

The 5GNR RRC signaling from 5GNR/LTE UEs 501 carries SRS. In 5GNR gNodeB521, the 5GNR PHY processes the SRS to determine radio metrics like AoAand received signal strength. The 5GNR MAC processes the radio metricsto determine 5GNR UE MU-MIMO correlation factors for groups of 5GNR/LTEUEs 501. The 5GNR MAC processes the radio metrics to determine UElocations for 5GNR/LTE UEs 501. The 5GNR MAC uses the UE MU-MIMOcorrelation factors to select and group UEs 501 for MU-MIMO. The 5GNRMAC schedules the selected 5GNR/LTE UEs 501 so that individual MU-MIMOgroups share individual DL 5GNR resource blocks. The 5GNR PHY transfersDL 5GNR signals so that the individual MU-MIMO groups share individualDL 5GNR resource blocks. In 5GNR/LTE UEs 501, the 5GNR PHYs isolatetheir specific 5GNR signal from the other 5GNR signals in the shared5GNR DL resource blocks.

In 5GNR gNodeB 521, the 5GNR MAC associates the UE MU-MIMO correlationfactors with the geographic containers based on UE locations. The 5GNRMAC averages the UE MU-MIMO correlation factors for individual groups ofthe geographic containers to determine container MU-MIMO correlationfactors for the groups of geographic containers. When the sample size(the number of UE correlations) for a group of geographic containersreaches a threshold, the 5GNR MAC begins to select 5GNR/LTE UEs 501 forMU-MIMO based on the container MU-MIMO correlation factors for thatgroup of geographic containers. The 5GNR MAC does not calculate UEcorrelation factors for the group of geographic containers until thesample size ages and needs to be refreshed. The 5GNR MAC schedules theselected 5GNR/LTE UEs 501 so that individual MU-MIMO groups shareindividual DL 5GNR resource blocks. The 5GNR PHY transfers DL 5GNRsignals so that the individual MU-MIMO groups share individual DL 5GNRresource blocks.

The LTE RRC signaling from 5GNR/LTE UEs 501 carries SRS. In LTE eNodeB522, the LTE PHY processes the SRS to determine radio metrics like AoAand received signal strength. The LTE MAC processes the radio metrics todetermine LTE UE MU-MIMO correlation factors for groups of 5GNR/LTE UEs501. The LTE MAC processes the radio metrics to determine UE locationsfor 5GNR/LTE UEs 501. The LTE MAC uses the UE MU-MIMO correlationfactors to select and group 5GNR/LTE UEs 501 for MU-MIMO. The LTE MACschedules the selected 5GNR/LTE UEs 501 so that individual MU-MIMOgroups share individual DL LTE resource blocks. The LTE PHY transfers DLLTE signals so that the individual MU-MIMO groups share individual DLLTE resource blocks. In UEs 501, the LTE PHYs isolate their specific LTEsignal from the other LTE signals in the shared DL LTE resource blocks.

In LTE eNodeB 522, the LTE MAC associates the UE MU-MIMO correlationfactors with the geographic containers based on UE locations. The LTEMAC averages the UE MU-MIMO correlation factors for individual groups ofthe geographic containers to determine container MU-MIMO correlationfactors for the groups of geographic containers. When the sample size(the number of UE correlations) for a group of geographic containersreaches a threshold, the LTE MAC begins to select 5GNR/LTE UEs 501 forMU-MIMO based on the container MU-MIMO correlation factors for thatgroup of geographic containers. The LTE MAC does not calculate UEcorrelation factors for the group of geographic containers until thesample size ages and needs to be refreshed. The LTE MAC schedules theselected 5GNR/LTE UEs 501 so that individual MU-MIMO groups shareindividual DL LTE resource blocks. The LTE PHY transfers DL LTE signalsso that the individual MU-MIMO groups share individual DL LTE resourceblocks.

The wireless data network circuitry described above comprises computerhardware and software that form special-purpose access node circuitry toefficiently group UEs for MU-MIMO using geographic container correlationfactors. The computer hardware comprises processing circuitry like CPUs,DSPs, GPUs, transceivers, bus circuitry, and memory. To form thesecomputer hardware structures, semiconductors like silicon or germaniumare positively and negatively doped to form transistors. The dopingcomprises ions like boron or phosphorus that are embedded within thesemiconductor material. The transistors and other electronic structureslike capacitors and resistors are arranged and metallically connectedwithin the semiconductor to form devices like logic circuitry andstorage registers. The logic circuitry and storage registers arearranged to form larger structures like control units, logic units, andRandom-Access Memory (RAM). In turn, the control units, logic units, andRAM are metallically connected to form CPUs, DSPs, GPUs, transceivers,bus circuitry, and memory.

In the computer hardware, the control units drive data between the RAMand the logic units, and the logic units operate on the data. Thecontrol units also drive interactions with external memory like flashdrives, disk drives, and the like. The computer hardware executesmachine-level software to control and move data by driving machine-levelinputs like voltages and currents to the control units, logic units, andRAM. The machine-level software is typically compiled from higher-levelsoftware programs. The higher-level software programs comprise operatingsystems, utilities, user applications, and the like. Both thehigher-level software programs and their compiled machine-level softwareare stored in memory and retrieved for compilation and execution. Onpower-up, the computer hardware automatically executesphysically-embedded machine-level software that drives the compilationand execution of the other computer software components which thenassert control. Due to this automated execution, the presence of thehigher-level software in memory physically changes the structure of thecomputer hardware machines into special-purpose access node circuitry toefficiently group UEs for MU-MIMO using correlation factors forgeographic containers.

The above description and associated figures teach the best mode of theinvention. The following claims specify the scope of the invention. Notethat some aspects of the best mode may not fall within the scope of theinvention as specified by the claims. Those skilled in the art willappreciate that the features described above can be combined in variousways to form multiple variations of the invention. Thus, the inventionis not limited to the specific embodiments described above, but only bythe following claims and their equivalents.

What is claimed is:
 1. A method of operating a wireless communicationnetwork to use Multi-User Multiple Input Multiple Output (MU-MIMO), themethod comprising: network circuitry storing geographic data thatindicates geographic containers; transceiver circuitry wirelesslyreceiving network signaling from User Equipment (UEs) that are locatedin the geographic containers; the network circuitry processing thenetwork signaling and responsively determining UE MU-MIMO correlationfactors between the UEs; the network circuitry processing the networksignaling and responsively associating the UE MU-MIMO correlationfactors with the geographic containers; the network circuitry processingthe UE MU-MIMO correlation factors associated with the geographiccontainers and responsively determining container MU-MIMO correlationfactors between the geographic containers; the network circuitryselecting other UEs for MU-MIMO based on their container MU-MIMOcorrelation factors; and the transceiver circuitry wirelesslytransferring MU-MIMO signals to the other UEs that were selected basedon their container MU-MIMO correlation factors, wherein the transceivercircuitry wirelessly transferring the MU-MIMO signals to the other UEscomprises using same time and frequency resource blocks for groups ofthe other UEs.
 2. The method of claim 1 wherein the network circuitryselecting the other UEs based on the container MU-MIMO correlationfactors comprises determining a sample-size for the container MU-MIMOcorrelation factors, using the container MU-MIMO correlation factorswhen the sample-size exceeds a sample threshold, and using the UEMU-MIMO correlation factors when the sample-size does not exceed thesample threshold.
 3. The method of claim 1 wherein the geographiccontainers comprise two-dimensional areas that are each smaller than 100meters by 100 meters.
 4. The method of claim 1 wherein the geographiccontainers comprise three-dimensional volumes that are each smaller than100 meters by 100 meters by 100 meters.
 5. The method of claim 1 whereinthe network circuitry determining the UE MU-MIMO correlation factorscomprises processing Sounding Reference Signal (SRS) information todetermine the UE MU-MIMO correlation factors.
 6. The method of claim 1wherein the network circuitry determining the UE MU-MIMO correlationfactors comprises executing a Fifth Generation New Radio Physical Layer(5GNR PHY) to determine the UE MU-MIMO correlation factors.
 7. Themethod of claim 1 wherein the network circuitry associating the UEMU-MIMO correlation factors with the geographic containers comprisesexecuting a Fifth Generation New Radio Physical Layer Media AccessControl (5GNR MAC) to associate the UE MU-MIMO correlation factors withthe geographic containers.
 8. The method of claim 1 wherein the networkcircuitry determining the container MU-MIMO correlation factorscomprises executing a Fifth Generation New Radio Physical Layer MediaAccess Control (5GNR MAC) to determine the container MU-MIMO correlationfactors.
 9. The method of claim 1 wherein the network circuitryselecting the other UEs for the MU-MIMO comprises executing a FifthGeneration New Radio Physical Layer Media Access Control (5GNR MAC) toselect the other UEs for the MU-MIMO.
 10. The method of claim 1 whereinthe transceiver circuitry comprises a Distributed Unit (DU).
 11. Awireless communication network to use Multi-User Multiple Input MultipleOutput (MU-MIMO) comprising: network circuitry configured to storegeographic data that indicates geographic containers; transceivercircuitry configured to wirelessly receive network signaling from UserEquipment (UEs) that are located in the geographic containers; thenetwork circuitry configured to process the network signaling andresponsively determine UE MU-MIMO correlation factors between the UEsand associate the UE MU-MIMO correlation factors with the geographiccontainers; the network circuitry configured to process the UE MU-MIMOcorrelation factors associated with the geographic containers andresponsively determine container MU-MIMO correlation factors between thegeographic containers and select other UEs for MU-MIMO based on theircontainer MU-MIMO correlation factors; and the transceiver circuitryconfigured to wirelessly transfer MU-MIMO signals to the other UEs thatwere selected based on their container MU-MIMO correlation factors,wherein the transceiver circuitry is configured to use the same time andfrequency resource blocks for groups of the other UEs.
 12. The wirelesscommunication network of claim 11 wherein the network circuitry isconfigured to determine a sample-size for the container MU-MIMOcorrelation factors, use the container MU-MIMO correlation factors whenthe sample-size exceeds a sample threshold, and use the UE MU-MIMOcorrelation factors when the sample-size does not exceed the samplethreshold.
 13. The wireless communication network of claim 11 whereinthe geographic containers comprise two-dimensional areas that are eachsmaller than 100 meters by 100 meters.
 14. The wireless communicationnetwork of claim 11 wherein the geographic containers comprisethree-dimensional volumes that are each smaller than 100 meters by 100meters by 100 meters.
 15. The wireless communication network of claim 11wherein the network circuitry is configured to process SoundingReference Signal (SRS) information to determine the UE MU-MIMOcorrelation factors.
 16. The wireless communication network of claim 11wherein the network circuitry is configured to execute a FifthGeneration New Radio Physical Layer (5GNR PHY) to determine the UEMU-MIMO correlation factors.
 17. The wireless communication network ofclaim 11 wherein the network circuitry is configured to execute a FifthGeneration New Radio Physical Layer Media Access Control (5GNR MAC) toassociate the UE MU-MIMO correlation factors with the geographiccontainers.
 18. The wireless communication network of claim 11 whereinthe network circuitry is configured to execute a Fifth Generation NewRadio Physical Layer Media Access Control (5GNR MAC) to determine thecontainer MU-MIMO correlation factors.
 19. The wireless communicationnetwork of claim 11 wherein the network circuitry is configured toexecute a Fifth Generation New Radio Physical Layer Media Access Control(5GNR MAC) to select the other UEs for the MU-MIMO.
 20. The wirelesscommunication network of claim 11 wherein the transceiver circuitrycomprises a Distributed Unit (DU).